Overall goals of this project are to: define the nature of the genes and linkage groups which code for, or otherwise affect the structure of immunoglobulins (Igs), to understand the regulatory processes which control Ig gene expression; to understand the mechanisms which lead to the synthesis of highly specific antibody molecules, and the nature of genes which influence and control immune responses. We have been defining by combined immunological and chemical approaches the structural differences between genetically controlled polymorphic forms of rabbit immunoglobulins (immunoglobulin allotypes) and between classes and subclasses, types and subtypes of their polypeptide chains. We utilize this information in designing a variety of studies including breeding experiments, studies of the ontogeny and differentiation of cells which produce Igs intracellularly, as secreted products, and as membrane-associated receptors, and studies of the factors which influence and regulate phenotypic expression of alleles or chain types. BIBLIOGRAPHIC REFERENCES: Werblin, T. and Mage, R.: A screening assay for rapid and quantitative measurement of immunoglobulins and anti-immunoglobulins in unknown sera. J. Immunol. Methods. In press, 1977. Mage, R.G., Rejnek, J., Young-Cooper, G.O. and Alexander, C.: Are "hidden" genes for immunoglobulin allotypes of rabbit heavy and light chains expressed upon hyperimmunization? Eur. J. Immunol., in press, 1977.